To begin, each term needs to be defined in order to understand what each term really means.

A fallacy is a mistake made upon an individual's reasoning. For example, if one makes an accident counting a number of things, they are making a mistake which is factual in nature (meaning there are more or less than the number counted by the person). Instead, if one believes that the ocean is a solid, they are making a mistake of reasoning (their reasoning is skewed).

A typical fallacy means a mistake which is made often. These are things which people tend to believe because the mistake has been made time and time again. It becomes a "truth" for some based upon its societal acceptance. An example of a typical fallacy is that cheese is mold. While some cheeses use a mold to speed the aging process, not all cheeses use or are mold.

A metaphor, on the other hand, is very different. A metaphor is a literary (or poetic/figurative) device in which a comparison is made between two or more things. For example, if one were to compare life to a rollercoaster (my life is a rollercoaster) then life and a rollercoaster are being compared (in order to create an image of one's life going in a path similar to that of a rollercoaster).